(i) Field of the Invention
The subject of this invention is a high frequency band-pass amplifier with adjustable impedance and also an oscillator including it.
(ii) Description of the Prior Art
Known high frequency band-pass amplifiers usually have high input and output impedances (of the order of several thousand ohms) which makes them sensitive to the thermal drift of the semiconductors they contain.
In addition, amplifiers used to produce high frequency oscillators (particularly in Hartley type configurations) also have input and output impedances of the same order of magnitude. A disadvantage of these high impedances is the degradation of the quality factor Q of the resonator included in the oscillator. Such an oscillator therefore has a characteristic frequency that is less stable than it could be.
The subject of this invention is a high frequency band-pass amplifier the impedance of which is adjustable and which, in particular, can have low value input and output impedances.
Such an amplifier is suitable for producing oscillators given that the input and output impedances can be low which prevents degradation of the quality factor Q of the resonator. In another connection, such an amplifier is also appropriate for the amplification of the signals output by an oscillator, in particular an oscillator according to the invention with low output impedance.